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1875 von Paul-Êmile Lecoq de Boisbaudran in Paris, Frankreich, entdeckt.
[Lateinisch, Gallia = Frankreich]
French: gallium
English: gallium
Italian: gallio
Spanish: galio
Beschreibung: Weiches, silberweißes Metall, beständig in Luft und Wasser. Löslich in Säuren und Basen. Hat den größten Flüssigkeitsbereich aller Elemente. Verbindungen mit Phosphor, Arsen und Antimon sind Halbleiter. Verwendet für Licht emittierende Dioden; Mikrowellengeräte.
Crystal structure: |
(cell dimensions/pm), space group, |
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X-ray diffractions mass absorption coefficients: | CuKa 67.9 (µ/r) / cm2g-1 MoKa 60.1 (µ/r) / cm2g-1 |
Neutron scattering length: | 0.7288 b/10-12 cm |
Thermal neutron capture cross-section: | 2.9 sa / barns |
Density: | 5907 kg/m-3 [293 K]; 6113.6 [liquid at m.p.] |
Melting point: | 29.78°C / 302.93°K |
Boiling point: | 2402.85°C / 2676°K |
Molar volume: | 11.81 cm3 |
Thermal conductivity: | 40.6 [300 K] W m-1K-1 |
Coefficient of linear thermal expansion: | 11.5 x 10-6 (a axis); 31.5 x 10-6 (b axis); 16.5 x 10-6 (c axis) K-1 |
Electrical resistivity: | 27 x 10-8 [273 K] Ωm |
Mass magnetic susceptibility: | -3.9 x 10-8(s) kg-1m3 |
Young's modulus: | 9.81 GPa |
Rigidity modulus: | 6.67 GPa |
Bulk modulus: | n.a. |
Poisson's ratio: | 0.47 GPa |
Radi: | Ga3+ 62; Ga+ 113; atomic 122; covalent 125 |
Electronegativity: | 1.81 (Pauling); 1.82 (Allred); ≤3.2 eV (absolute) |
Effective nuclear charge: | 5.00 (Slater); 6.22 (Clementi); 6.72 (Froese-Fischer) |
Number of Isotopes (incl. nuclear isomers): | 23 |
Isotope mass range: | 62-> 83 |
Biological role: | None, but gallium acts to stimulate metabolism. |
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Toxicity | |
Toxic intake: | < 15 mg kg-1 tolerated without apparent harm |
Lethal intake: | LD50 (chloride, injection, rat) = 47 mg Kg-1 |
Hazards: | Gallium salts generally have low toxicity. |
Level in humans | |
Blood: | <0.08 ppm |
Bone: | n.a. |
Liver: | 0.0025 ppm |
Muscle: | 0.0014 ppm |
Daily dietary intake: | n.a. but low |
Total mass of element in average [70 kg] person: |
< 0.7 mg |
Minerals: | Gallium minerals are rare, but gallium occurs in other ores to the extent of 1%. | |||
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Mineral | Formula | Density | Hardness | Crystal apperance |
Gallite | CuGaS2 | 4.40 (calc.) | 3 - 3.5 | tet., met. grey |
The ores diaspore, sphalerite, germanite and bauxite contain traces of gallium. Coal can also have a high gallium content.
Chief ores: | Gallium is recovered as a by-product of zinc and copper refining |
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World production: | 30 tonnes/year |
Main mining areas: | see copper and zinc. |
Reserves: | n. a. |
Specimen: | available as ingot, and as ultrapure gallium. Safe. |
Abundances | |
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Sun: | 631 (relative to H = 1 x 1012) |
Earth's crust: | 18 ppm |
Seawater | 3 x 10-5 ppm |
Residence time: | 10 000 years |
Classification: | n.a. |
Oxidation state: | III |
Source: Emsley, J. (1998) The Elements (3rd Edition)
Other sizes and specifications on request